Final Verification Test Research Articles

Rain-Like Layer Removal From Hot-Rolled Steel Strip Based on Attentive Dual Residual Generative Adversarial Network

Rain-like layer removal from hot-rolled steel strip surface is proved to be a workable measure for suppressing the false alarms frequently triggered in automated visual inspection (AVI) instrument. This paper extends the scope of “rain-like layer” from dispersed waterdrops to splashing water streaks and tiny white droplets. And a targeted method with both channel-wise and spatial-wise attention, namely attentive dual residual generative adversarial network (ADRGAN), is proposed. Meanwhile, a newly updated steel surface image dataset with typical natures of “rain-like layer” gathered from actual hot-rolling line, Steel_Rain, is opened for the first time. The comparison experimental results between our proposed network and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eleven</i> prestigious networks show that our ADRGAN-restored images are the closest to the ground-truth images on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">six</i> public datasets, especially on the newly-opened industrial dataset Steel_Rain, it yeilds the best scores of 56.8627 peak signal to noise ratio (PSNR), 0.9980 structural similarity index (SSIM), 0.134 mean-square error (MSE) and 0.006 learned perceptual image patch similarity (LPIPS). In the final verification test, the concept of rain-like layer removal has been proved to perform best in defect inspection, where <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">four</i> traditional defect detection algorithms are involved. And as expected, defect detection methods assisted by ADRGAN yield the minimum false-alarms <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> .

Implementation of a D-STATCOM control strategy based on direct power control method for grid connected wind turbine

Distributed generation (DG) is getting increasing relevancy on the electric energy production. In Tunisia, the increase of the installed wind power has an impact on the grid transmission due to the intermittence of production. Grid operators have now enough field experience to adapt the existing grid codes to the new energy mix. DG systems have proved that they can contribute to grid stability using power converters and control algorithms. Therefore, the installation of the FACT devices is necessary to guarantee the high energy quality and electrical grid stability. STATCOMs present the FACTs which are currently used. This paper presents the main effects of the DG connection to a grid and the role of STATCOM to reduce undesirable effects, making the DG fully operable. Thus, a STATCOM control strategy based on DPC is proposed to show the impact of this device on the quality of electrical power system. The advantage of the proposed technique is to enhance the voltage profile in steady state operation and under different working conditions and sags voltage. Moreover, STATCOM improves the transient voltage stability and therefore helps the wind turbine generator system to remain in service during grid faults. The proficiency and functionality of the proposed controller are demonstrated through detailed theoretical analysis. Computer simulation using the Matlab/Simulink software is performed. Accordingly, a hardware prototype employing a dSpace 1104 board -based system is built for final verification test. Experimental results show that the proposed control method is very effective.

A New Method of Lithology Classification Based on Convolutional Neural Network Algorithm by Utilizing Drilling String Vibration Data

Formation lithology identification is of great importance for reservoir characterization and petroleum exploration. Previous methods are based on cutting logging and well-logging data and have a significant time lag. In recent years, many machine learning methods have been applied to lithology identification by utilizing well-logging data, which may be affected by drilling fluid. Drilling string vibration data is a high-density ancillary data, and it has the advantages of low-latency, which can be acquired in real-time. Drilling string vibration data is more accessible and available compared to well-logging data in ultra-deep well drilling. Machine learning algorithms enable us to develop new lithology identification models based on these vibration data. In this study, a vibration dataset is used as the signal source, and the original vibration signal is filtered by Butterworth (BHPF). Vibration time–frequency characteristics were extracted into time–frequency images with the application of short-time Fourier transform (STFT). This paper develops lithology classification models using new data sources based on a convolutional neural network (CNN) combined with Mobilenet and ResNet. This model is used for complex formation lithology, including fine gravel sandstone, fine sandstone, and mudstone. This study also carries out related model accuracy verification and model prediction results interpretation. In order to improve the trustworthiness of decision-making results, the gradient-weighted class-activated thermal localization map is applied to interpret the results of the model. The final verification test shows that the single-sample decision time of the model is 10 ms, the test macro precision rate is 90.0%, and the macro recall rate is 89.3%. The lithology identification model based on vibration data is more efficient and accessible than others. In conclusion, the CNN model using drill string vibration supplies a superior method of lithology identification. This study provides low-latency lithology classification methods to ensure safe and fast drilling.

Design and Implementation of a STATCOM Based on a Multilevel FHB Converter with Delta-Connected Configuration for Unbalanced Load Compensation

A delta-connected STATCOM with cascade multilevel full H-bridge (FHB) converter has been applied for phase balancing and power factor correction of unbalanced load in a three-phase, three-wire power distribution system. In this paper, a feedforward compensation formula is presented for the STATCOM by using the symmetrical components method to compensate unbalanced load. Computer simulation is performed for preliminary verification. Accordingly, a hardware prototype employing a TMS320F2812 DSP-based system is built for final verification test. Experimental results show that the proposed STATCOM is very effective for real-time unbalanced load compensation.

22.2 ch Audio Encoding/Decoding Hardware System Based on MPEG-4 AAC

A 22.2 multichannel (22.2 ch) sound system has been adopted as an audio system for 8K Super Hi-Vision (8K). The 22.2 ch sound system is an advanced sound system composed of 24 channels three-dimensionally located in a space to envelop listeners in an immersive sound field. NHK has been working on standardizing and developing an 8K broadcasting system via a broadcasting satellite in time for test broadcasting in 2016. For an audio coding scheme, NHK developed a world-first 22.2 ch audio encoding/decoding hardware system (22.2 ch audio codec) capable of real time encoding/decoding. The fabricated 22.2 ch audio codec is based on MPEG-4 AAC and was assembled into the 8K codec together with the 8K video codec and the multiplexer. The audio quality of the fabricated 22.2 ch audio codec was assessed in an objective evaluation, and the evaluation results revealed the operational bit rates of the fabricated codec. An 8K satellite broadcasting experiment was carried out as a final verification test of the 8K broadcasting system, and 22.2 ch audio codec was found to be valid.

A Modeling Method for HVDC Control on RTDS Simulation

Converter control model plays an essential function for HVDC system dynamic simulation in real time simulator (RTDS). RTDS can provide approach for detailed studies of options and predictions of the system performance. This paper first presents the basic principle of the power control, firing control and transformer tap control. Then the paper presents our modeling effort for these control models. The configuration of control models includes major sections of practical controls. The paper also makes final verification test of these sections with a typical power system model. The validity of proposal methods and designed simulation model is verified by tests and computed results. The built HVDC control model is competent for the RTDS simulation.

Development and Verification of 3000 Rpm 48 Inch Integral Shroud Blade for Steam Turbine

The 3000rpm 48inch blade for steam turbine was developed as one of the new standard series of LP end blades. The new LP end blades are characterized by the ISB (Integral Shroud Blade) structure. In the ISB structure, blades are continuously coupled by blade untwist due to centrifugal force when the blades rotate at high speed. Therefore, the number of the resonant vibration modes can be reduced by virtue of the vibration characteristics of the circumferentially continuous blades, and the resonant stress can be decreased due to the additional friction damping generated at shrouds and stubs. In order to develop the 3000rpm 48inch blade, the latest analysis methods to predict the vibration characteristics of the ISB structure were applied, after confirming their validity to the blade design. Moreover, the verification tests such as rotational vibration tests and model turbine tests were carried out in the shop to confirm the reliability of the developed blade. As the final verification test, the field test of the actual steam turbine was carried out in the site during the trial operation, and the vibration stress of the 3000rpm 48inch blade was measured by use of telemetry system. In the field test, the vibratory stress of the blade was measured under various operating conditions for more than one month. This paper first presents the up-to-date design technology applied to the design of the 3000rpm 48inch blade. In the second place, the results of the various verification tests carried out in the shop are presented as well as their procedure. Lastly, the results of the final verification tests of 3000rpm 48inch blade carried out in the site are presented.